8040213: C2 does not put all modified nodes on IGVN worklist Summary: Verification code is added that checks if modified nodes are put on the IGVN worklist and modified nodes are processed by 'PhaseIterGVN::transform_old()' Reviewed-by: kvn, jrose

^build/
^dist/
^drop/
^drop_included/
^webrev/
/nbproject/private/
^.hgtip